1. Tissue culture media will be modified in an attempt to cause tissue cultured corneal endothelial monolayers to acquire their normal functional state as indicated by their electrical properties. 2. Perfusion media will be modified so as to maintain the cornea of a perfused isolated eye in good condition for as long as possible. The behavior of the tissue will be compared with that of an isolated cornea perfused with the same medium, in order to test whether a component secreted by the ciliary body is essential to its welfare. 3. The kinetics of the different cell types within an injured corneal stroma will be followed in order to clarify their origins, transformations and fate. 4. The cellular reactions to corneal injuries in the isolated perfused eye, in the confines of the stroma, and under a glued-on on contact lens will be examined, with a view to identifying the cellular and stimulatory contributions from the blood and tears. 5. Liposomes suspended in physiological medium will be used as indicators of fluid flow across the endothelial surface in order to determine whether the fluid pump operates between or across the cells. 6. An electrochemical potential difference of Na, K, Cl and HCO3 across the endothelium will be looked for by bringing ion- sensitive electrodes close to the cell layer and blocking ion fluxes. The development of a potential step will establish that an ion is involved in an active transport mechanism.